Harrington said becoming chief constable had been “a pinnacle of my career”, and after 36 years of policing he was feeling “a little bit apprehensive” about the future.
“I’m probably a little bit institutionalised… [but] it’s the right time for me to move on, so I’m really excited… for whatever the next chapter is for me.”
Harrington said he had no other job lined up, but would not rule anything out in the future.
The day after retiring, he plans to embark on a 1,118 mile (1,800km) cycle ride to visit historical castles.
“I’ve got a ferry booked going over to France with me, my bike and my tent,” he said.
“I have become a bit of a history geek thanks to a podcast on Plantagenet history… so I’ll be dotting my way across France visiting Plantagenet castles and history points.”
Harrington said he would then meet up with his wife in the south of France “for a proper holiday”, where he was looking forward to spending time “without all the responsibility, power and late-night phone calls”.
Deputy Chief Constable Rachel Nolan is due to take over from Harrington, after his retirement on 31 August.
She will become the first female to lead the force.
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